- Day 0 will be settled from 24h to 48h after fludarabine treatment completion. NK cells will be intravenous administered twice (day 0 and day 7). The first dose of NK cells (day 0) will contain up to 5x10^7 cells/kg with immunophenotype NK (CD3-CD56+). The second dose might be higher (up to 5x10^8 cells/kg) in case of no treatment related toxicity after first NK injection. In any case, no more than 1x10^6 cells/kg with an immunophenotype T (CD56-CD3+) will be administrated.